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作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　September 25, 2009 — 免疫執業顧問委員會（ACIP）更新並取代過去對腦膜炎球菌延長高風險病患再次接種的建議。這項於2009年6月24日於ACIP會議通過的指引，9月25日發表於死亡率與發病率週報。
　　
　　ACIP過去建議所有11至18歲的青少年、以及2至55歲且處於腦膜炎疾病風險的人們都應該接種四價腦膜炎球菌接合疫苗（MCV4；Menactra；賽諾菲巴斯德公司）。雖然MCV4被核准以單一劑量投予，ACIP現在建議處於腦膜炎球菌疾病風險，因為醫療疾病或是延長時間暴露的病患都應該每5年接種一次MCV4。
　　
　　ACIP腦膜球菌疫苗工作小組寫到，因為特定族群感染腦膜炎球菌的風險較高，且有關疫苗保護力時間長度的資料不足，在6月的2009年ACIP會議中，建議過去接種過MCV4或MPSV4（Menomune，賽諾菲巴斯德藥廠）的感染腦膜炎球菌疾病長期高風險群應該重新接種MCV4。7歲以上疫苗接種者，以及長期處於高風險者，應該在接種腦膜炎球菌疫苗5年後重新接種，而過去於2-6歲接種疫苗，且長期處於高風險群者，應該在3年後重新接種。一直持續處於高風險的族群應每5年接種一次。
　　
　　使人們持續處於感染腦膜炎球菌疾病高風險的因子，包括持續的補體缺乏（例如C3、備解素、D因子、以及後期補體缺乏），解剖或是功能性脾臟功能喪失、以及延長暴露（例如經常處理奈氏腦膜炎球菌的微生物學家、或是到腦膜炎球菌大流行或流行國家旅行或居住的人們）。
　　
　　目前，並不建議對於過去已接種過MCV4的住宿大學生重新進行接種。然而，住宿的、以及已經接種MPSV4超過5年的大學新鮮人，應該重新接種MCV4。
　　
　　來自ACIP腦膜炎球菌疫苗工作小組的新建議是根據回顧腦膜炎球菌疾病風險、抗體力價的下降、以及接種MCV4 3年或MPSV4 5年後重新接種的免疫功能與安全性。
　　
　　對抗奈氏腦膜炎球菌的高血清殺菌抗體可以提供長期處於腦膜炎球菌疾病人們更多的保護力。研究中，所有重新接種MCV4的人們對血清型C與Y都達到大於1:128的殺菌抗體效價。過去接種與未接種的人們，在重新接種或一開始接種MCV4時，大約50%至70%的人們報告有輕度至中度的局部與全身反應，但是這兩組都沒有發生嚴重的不良反應。
　　
　　ACIP腦膜炎球菌疫苗工作小組寫到，根據這些數據，工作小組成員的專家意見，以及來自合作組織的回饋，工作小組提議長時間處於腦膜炎球菌疾病高風險群的人們應該重新接種MCV4。雖然MCV4的保護期未知，大部分的大學入學學生將會在接下來的4年接種MCV4。因為風險增加的時間有限，ACIP目前並不建議過去接種過MCV4的住宿大學新鮮人重新接種。
　　
　　有關於2至55歲接種MCV4的資訊與其他建議過去已經發表。這包括11至18歲的青少年可以接種MCV4的常規建議。

New Guidelines Recommend Revaccinating Those at Prolonged Increased Risk for Meningococcal Disease

By Laurie Barclay, MD
Medscape Medical News

September 25, 2009 — The Advisory Committee on Immunization Practices (ACIP) has updated and replaced its previous recommendations for revaccinating persons at prolonged increased risk for meningococcal disease. The new guidelines, which were approved at the June 24, 2009, ACIP meeting, are published in the September 25 issue of the Morbidity and Mortality Weekly Report.

ACIP has previously recommended quadrivalent meningococcal conjugate vaccine (MCV4; Menactra, Sanofi Pasteur) for all persons aged 11 to 18 years, as well as for persons aged 2 to 55 years who are at increased risk for meningococcal disease. Although MCV4 is licensed as a single dose, ACIP now recommends that persons at increased risk for meningococcal disease for prolonged periods of time because of medical conditions or because of prolonged exposure should be revaccinated with MCV4 every 5 years.

"Because of the high risk for meningococcal disease among certain groups and limited data on duration of protection, at its June 2009 meeting ACIP recommended that persons previously vaccinated with either MCV4 or MPSV4 (Menomune, Sanofi Pasteur) who are at prolonged increased risk for meningococcal disease should be revaccinated with MCV4," writes ACIP's Meningococcal Vaccine Work Group. "Persons who previously were vaccinated at age ?7 years and are at prolonged increased risk should be revaccinated 5 years after their previous meningococcal vaccine, and persons who previously were vaccinated at ages 2–6 years and are at prolonged increased risk should be revaccinated 3 years after their previous meningococcal vaccine.... Persons who remain in one of these increased risk groups indefinitely should continue to be revaccinated at 5-year intervals."

Conditions placing persons at prolonged increased risk for meningococcal disease include persistent complement component deficiencies (such as C3, properdin, Factor D, and late complement component deficiencies), anatomic or functional asplenia, and prolonged exposure (eg, microbiologists routinely working with Neisseria meningitidis, or travelers to or residents of countries where meningococcal disease is hyperendemic or epidemic).

At this time, it is not recommended that college freshmen who live in dormitories but who were previously vaccinated with MCV4 be revaccinated. However, college freshmen who live in dormitories and who were vaccinated with MPSV4 5 or more years previously should be vaccinated with MCV4.

The new recommendations from ACIP's Meningococcal Vaccine Work Group are based on a review of data on the risk for meningococcal disease, decrease in antibody titer, and the safety and immunogenicity of revaccination with MCV4 at 3 and 5 years after the first dose of MCV4 or MPSV4.

Higher levels of serum bactericidal antibody against N meningitidis can offer increased protection to persons with prolonged increased risk for meningococcal disease. All persons revaccinated with MCV4 in the reviewed studies reached serum bactericidal antibody titers greater than 1:128 for serogroups C and Y. About 50% to 70% of persons in previously vaccinated and in unvaccinated groups reported mild to moderate local and systemic adverse events after revaccination or initial vaccination with MCV4, but no serious adverse events were reported in either group.

"On the basis of these data, expert opinion of the workgroup members, and feedback from partner organizations, the workgroup proposed that persons at prolonged increased risk for meningococcal disease be revaccinated with MCV4," the ACIP Meningococcal Vaccine Work Group writes. "Although the duration of protection from MCV4 is unknown, most entering college students will have received MCV4 within the preceding 4 years. Because of the limited period of increased risk, ACIP currently does not recommend that college freshmen living in dormitories who were previously vaccinated with MCV4 be revaccinated."

Information regarding MCV4 and other recommendations for individuals aged 2 to 55 years has been published previously. This includes a routine recommendation that persons aged 11 to 18 years be vaccinated with MCV4.

Morb Mortal Wkly Rep. 2009:58;1042–1043.